[en] For obtaining the time history acceleration responses for updated KALIMER reactor building, lumped-mass beam models composed of two sticks for the reactor building and the reactor support structure are developed. The simple model for KALIMER reactor building has 15 lumped masses and 14 beam elements. The 174 isolators of isolated building are grouped to 10 lumped-spring elements with 3 degrees of freedom in translation. The time history responses of accelerations and displacements for the non-isolated and isolated reactor buildings are calculated with respect of an artificial acceleration time history, generated using the seismic spectrum curve of US NRC RG1.60. The analysis results show that the horizontal accelerations of the isolated building are dramatically decreased to one-tenths of the non-isolated one, but the vertical responses are increased by about 42%, which is similar with the results of response spectrum analyses. For the isolated case, the over turning moments occurred in this analysis are quite small level, and the rotational mode of isolated building is not amplified